The present invention relates to a flow-rate limiting device in a single-control mixer cartridge for hot and cold water.
The widespread use of mixer cartridges is known; these cartridges are inserted in faucets and allow, by operating with a single actuation lever, both to vary the flow-rate delivered by the faucet from zero to a maximum value and to vary the temperature-of the water by appropriately mixing the hot and cold water that reach the faucet.
These devices comprise, inside a portion of space defined by a bottom with openings for the separate inflow of hot and cold water and for the outflow of hot, cold or mixed water and by a body associated with the bottom, a fixed plate made of ceramic material, which is provided with holes matching the openings of the bottom, and also comprise a movable plate, also made of ceramic material, which internally defines a mixing chamber and is associated, with a plate cover interposed or not, with said actuation lever, which is pivoted on a coupling rotatable within said body.
In this manner the movable plate can assume different positions with respect to the fixed plate, and in particular it is known that a movement of the lever about the fulcrum changes the water flow-rate, whereas rotation of the coupling varies the temperature of said water.
Due to reasons related to user requirements, it may be needed to reduce the maximum dispensed flow-rate, and for this purpose the known art provides devices usually associated with the faucet in which the cartridge is inserted; these devices have constructive complications and do not offer reliable operation.